Process of drawing sheet glass



K H. G. LlNGLUFF PROCESS 0F DRWING Film March #26, 1923 5 Sheets-#Smet 1 Z .10 Z 3 mw B M4 i Sept. 22, 1925.

H. G. SLNGLUFF PROCESS OF DRAWING SHEET GLASS Filed March 26, 1923 5 Sheets-Sheet 2 E9 wm W 5 M .V Ji .Il O M n n Q w un O n 5T 2M M -i In.

INV NToR.

FEF

5 f A TToRNEY.

sept 23, 19.25.

1,554,886 H. G. sLuNGLur-F PROCESS 0F DRAWNG SHEET GLASS Filed.. Maron 2s, 192s 3 SheetS-Sheet I5 IN ENT R.

ATTORNEY.

Patented Sept. 22, `1925.

UNITED ,STATES malata PATENT oFFlcE- may e. SLINGLUFF, or MoUNr vEnNoN, onro, AssreNon To rrrrsnunen anatra @Lass COMPANY, A CORPORATION or PENNSYLVANIA.

:PROCESS OF DRAWING SHEET GLASS.'

, ,.Application led March 26, 1923. Serial No. 627,673.

To all whom it may concem: Be it known that I, HARRY G. SLINGLUFF, a citizen of the United States, and a resident lof Mount Vernon, in the county of Knox and State of Ohio, have made a new and `useful invention in Improvements in Processesof Drawing Sheet Glass, of which the following is a specification.

The invention relates to a process for T10 drawing sheet glass, the apparatus preferabl employed being similar to that` shown and7 claimed in lmy application for U. S. Letters Patent, Serial Number 621,184. It has for its principal object the provision l5 of an improved process for producing a continuousribbon of sheet glass whereby the glassmay be produced economically, with a minimum amount of breakage, Without marringyand annealed and cooled to a point 0 where it may be readily cut intov sections. The apparatus preferably `employed in carrying out the process is shown in the accompanying drawings, wherein:

Figure 1 is an end elevation of the apparatus. Fig. 2 is a Jfront elevation with the curtain or belt on the near side removed in order to show certain of the parts which would otherwise be covered. Fig. 3 is a plan view. Fig. 4 is a detail view of a small section of one of the curtains or belts showing the reinforced construction of the lfabric ,and Fig. 5 is aperspectivev detail view..

The drawing apparatus 'to which the present invention relates is shown as located above the tank construction. preferably em- 1oyed,but is not limited to use 'with such orm of tank. The tank includes a melting 'f tank or furnace of the regenerative type which is not shown and a drawing tank 1 containing a bath `of molten glass and the clay (members 2, -3 and 4 lying in suel bath, 2 and 4 being. skimming bars and 3 a guide bar located beneath the line of generation of the sheet 5. The tank is provided with suitable burnersv 6 and 7 and with L-shaped 'shieldingl members- 8 and 9, lying above the bath on opposite sides of the sheet.

The main .force for the sheet is applied by means of the endless belts or curtains 10 and 11 made of ashes-.tts fabric and the sets ofdriven rolls 12 and 13 and 14 and. 15, the rolls Lbeing of themselves suilieient to draw the sheet, while the belts act as in sulators and supplement the drawing action of the rolls. The belts 10 and 11 are made of woven asbestos fabric, diagrammatically shown in Fig. 4, such fabric having itsstrands 16 reinforced by the tine metal wires 17, each of which is embedded in the asbestos, Thls wire reinforcing gives the necessary strength to the fabric, while the asbestos protects the wires from the action of the heat and provides a relatively sott flexible refractory surface for contacting with the glass. The drawing rolls 12 and 13 and '14 and 15 are also covered with a similar fabric of, which there may be sev-- eral layers, thus giving a yielding Contact with the glass sheet and avoiding any scratching or marring which might otherwise be present with rolls having metal con tacting surfaces.

The belts l0 and 1l are driven from the pulleys 18 and 19 at the upper ends of the apparatus and tension is applied to the belts at their lower ends by means oi the steel bars 2O and 21` placed in the 'lower ends thereof. These bars' 20 and 21 are circular in cross section and are supported entirely by the belts. The pulleys 1.8 and l@ are preferably spaced apart as indicated in Fie. 1 so that no pressure is'appiied by such rolls to the glass sheet 5 which passes therebetween. In this wayany tendency 'to breakthe glass is avoided which might otlzuerwise occur if the glass. as it was not perfectly dat.

The pulleys 18 and 19 are driven frondje.

passed these VVpulleys counter shafts carry at the ends the sprockets 24 and 25 geared to corresponding sprockets 26=and 27 ion the ends of the titipair ofA counter shafts 22 and 23 which use' 'protect the rolls 14 and 15 and they in turn protect the belts 10 and 11. In this way, the use of the drawing devices beneath the belts involves a greatsaving in upkeep, as thelife of the. belts is increased. The cost of the belts, udue to the quantity of material involved is very much greater than that of the drawing rolls beneath. i

In case of breakage of the glass between the belts, it is often possible to continue the 4drawing operation because of the use lof the rQlls 12and 13 and 14 and 15. The pressure lexerted by these rolls is sufficient to continue the pulling of the lass even when the break extends to a point iltains. The rolls also steady the glass` sheet and tend to maintain it in its proper positionwith respect to the bath. Due to inequalities in the temperature vof the glass bath, thereis a certain tendency at times for thesheet to move4 so that its linelof generation is off. .center with respect to the eenu ter line of the` 'de bar 3,an'd in such case, ythe drawing ro apply a constant pressure tending to -correct this condition andy bring the sheet Vto its proper position. They also' rotect the sheet Ufromtheheat of the bath neath so ,thatthefglass enters the belts i at a lower-.temperature than would-other- 4wisebe the case. As a resultthe sheet pa through and-leaves the belts at a lower temperature than would otherwise be` the case,

Vrendering it easier to cut and handleg The l temperature ,conditions are such that the :i is .practically annealed before it enters belts having a temperature ordinarily rangingrom v500 to 700 F. and in no case -over\900 F. The-conductin quality ofthe belts is `such thatthe'rglass rops from this temperature to approximately 150 to 250 F. in its passage? to the upper end of the apparatus, at which point 1t is cut ott, This rate of coolmgis slow enough tol prevent any substantial breakage and yet suiciently rapid to rmit of proper handling and cutting of t e glass upon its emergence from the curtains. rThis relatively rapid cooling is due to the fact'that the belts are composed n ot a relatively thin wovenl texture with nothingto preventthe 'dispersion of heat E from the rear faces of the belt ilights in contact with the glass.

` The idimensions af the apparatus and its location withy respect to the bath will vary `depending upon conditions, but in drawing at from 20 to'30 inches per minute, the lower ends of the belts may be located about 4 feet from the surface of the glass and that sol the belts are of such length that their upper ends are about 13 feet from the surface of the glass.

In order to permit the passage of a bait between the belts and the glass in starting the operation, the bell crank hangers 63, 76, 77, 7 8 and 79 may be connected by means neath the curvThe cooling of chains 84 soas to be operated in unison,

and one of such hangers on cach side of the machine may be connected with a crank arm 85 mounted on the shaft 86 by means of the bar 8L The shaft 86 is provided wthi'IO a suitable rotating Imechanism (not shown) so that by turning on this shaft the lever 85 may be moved upward, thus moving all of the counterweighted arms upward and swinging the rollers o7, 68, 69, 70 and' 71 75 outward away from the curtain so that such curtain vmay move, to the rear. The cooling `of the glass in'its passage through thebelts orcurtains is promoted by the use of the'air pipes 88, one oit which is SJ shown in Fig. 2. These pipes are placed just/to the rear ci the inner nights oi the curtains and have a series of perici'ation's directed toward vthe. curtains. ,Air is lsupplied frorn a :ian 4or other suitable source, 85

4and serves to reduce' the temperature oi the curtains and the glass passing therebetween.

renders the glass easierto handle and cut. f

thatV l'. claim is:

. 1. -A process of producin sheet glass which consists in drawing a s eet vertically and continuously' from a molten bath, permitting the sheet to cool and annealin the heat from the bath' to a temperature below 95 '900 FL, then applying insulating means moving with the glass to the opposite sides thereof, wfhile the glass is cooling to a term. perature at which it may be cracked oii, and finally cracking the glass o'.

2.` A process of producing sheet glass continuous y from-a glass Vbath which consists` in applying drawing force to the opposite sides of the .sheet above the surface of the bath,`chilling the glass below the point of application of-said force so that the glass is at a temperature below that at which the glass sets when such force is applied, and applying insulating means to the opposite',v i l si es of the sheet above the point ofappli- 11e cation of said torce until the sheet .is reduced y in temperature to a point -at which it may be cracked ofi.

3. Aprocess of producing 'sheet glass continuously from a glass bath 4which consists 115 in applying rotating trictional drawing means to the sides of the sheet above the surface of the bath suiiicient to continuously draw the sheet, chilling the glass by radiation, below said means, so that the sheet is below its temperatureof setting when it reaches said drawing means, and applying a heat insulation against the sides of the sheet above the drawing means and contin- Y uing said insulation until the glass cools suiciently to be cracked off.

4. A. process of producing sheet glass which consists in, drawing a sheet vertically and continuously from an open molten bath,

permitting the glass to cool and anncal in 130 

